In a wet type developing apparatus of this sort, a liquid developer is supplied onto the surface of a developing roller from a developer supply roller whose peripheral surface is in part immersed in the liquid developer. The developer roller is driven in rotational contact with a photoconductor drum whereby an electrostatic latent image made on a surface of the photoconductor drum is developed with the liquid developer. And, the developer supply roller in general is used comprising an anilox roller provided with cellular recesses in the form of a mesh to retain a proper amount of the liquid developer on its surface.
While the toner should be supplied from the developer supply roller onto the developing roller in a proper amount and evenly, there arises a problem with such a developer supply roller that with lapse of time, toner particles and additionally foreign matters tend to adhere on its surface and, as they accumulate in the cells, the supply of the toner onto the developing roller deteriorates gradually in accuracy, deteriorating the printing quality.
For this reason, developer supply rollers of this kind have had to be cleansed periodically.
In conventional methods of cleansing the surface of a developer supply roller in an developing apparatus, the developer supply roller is dismounted from the developing apparatus and then immersed in a detergent, or in the state that it is immersed in a detergent it is given ultrasonic vibrations, or in the state that it is immersed in a detergent it is rubbed with a cleaning member (JP H07-89627 A; JP H07-125187 A).
In these conventional methods, however, it should be noted that each time a developer supply roller in a wet type developing apparatus in an electrophotographic printer requires cleansing, the developer supply roller must be dismounted from the developer apparatus, must then be cleansed, being put in a separately built cleansing unit and must thereafter be re-mounted on the developing apparatus. Problems ensue: the need for the separately built cleansing unit, the need for operations by an operator or operators to dismount, to cleanse and to re-mount the developer supply roller; they are much burdensome in terms of time, labor and economy.